The impact of combination of solution plasma processing and pulsed electric field on the viability of probiotic bacteria, microbial growth, and structure of yoghurt drink

Abstract

In this study, the properties of the milk treated with combination of solution plasma (SP) processing and pulsed electric field (PEF) for different periods (5 and 10 min) was investigated. The microbiological, physicochemical, and sensory properties of the probiotic yoghurt drink (Ayran) produced from these milks were determined during storage. PEF was performed at voltage 3500 V, repetition 17,000 Hz, and pulse width 2.58 mu s on the raw milk. Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis probiotic cultures were used in production with conventional yoghurt bacteria Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. In addition to the probiotic viability, texture and sensory quality in terms of consumer preference were investigated. It was determined that the viscosity and dry matter values of the solution plasma-treated samples were lower compared to the samples produced by heat treatment, and these values decreased further with the increase in plasma application time. It was also found that the maximum increase in L* and b* values of all samples during storage was in the samples treated with plasma for 10 min. The viability of the probiotic bacteria in probiotic Ayran samples were determined to be within the therapeutic level (>6.27 log(10) cfu ml(-1)) with higher scores for sensorial qualifications. Practical applications Consumers' expectations of more nutritious and microbiologically safe food have enabled the development of new processing technologies. Probiotic fermented milk products are products that provide health benefits in the prevention of gastrointestinal diseases, regulation of metabolism, and stimulation of the immune system. The processing of these dairy products with non-thermal technologies provides advantages in preserving their functional properties.